Currently, there are no vaccines for protection against Clostridium septicum infection in humans. Alpha toxin is produced by C. septicum and is its main lethal factor. In humans, the population of at-risk individuals for a C. septicum infection includes colonic cancer patients, diabetics, leukemia patients, and neutropenics.
Vaccines for animals are available but currently are made from killed whole C. septicum cells which cannot be used in humans. Moreover, such whole-cell vaccines have several disadvantages even when used in animals. For example, when the vaccine is used in cattle, there is significant loss of prime cuts of beef since the vaccination site is the loin area which yields some of the most valuable cuts of meat, such as tenderloin steak. Since the whole-cell vaccination results in such economic losses, other vaccines which do not result in the destruction of this meat are desirable. Furthermore, the production of killed whole-cell vaccines is difficult since these vaccines need to be extensively quality-tested prior to use, and even then there can be vaccine failures. The problems associated with killed whole-cell vaccines could be eliminated by producing a vaccine containing an immunogen which can be easily quality-tested and which is genetically inactive.